Having just bought my first double rifle, and still really needing to understand regulation properly, how do you go about developing a load for them?

Do you work up and accurate load in one barrel, and then if or at what distance both barrels shoot together (which is my limited understanding of what regulation is) and see if that's acceptable or is there a better method?

It's only for club use, and is a baby in .30-06 so I can run pretty much any 30cal bullet and don't need powerful loads either.

Thanks, Jeff